Add title field sync for collection nodes (Issue #844)

[malibio]

Summary

• Enable indexed title field for collection nodes to improve lookup performance
• Exclude collections from @mention autocomplete results
• Update collection lookup methods to use indexed title instead of unindexed content

Changes

node_service.rs

• Modified create_node() to set title for collection nodes (in addition to task nodes)
• Modified create_node_with_parent() to include collections in title sync
• Modified update_node() to sync title when collection content changes
• Added comprehensive test module for collection title sync behavior

surreal_store.rs

• Updated get_collection_by_name() to query indexed title field instead of unindexed content
• Updated get_collections_by_names() to query indexed title field for batch lookups
• Added node_type != 'collection' filter to mention_autocomplete() to exclude collections
• Added tests for collection lookup using title field and @mention exclusion

Test plan

• Run cargo test -p nodespace-core --lib collection_title - 4 tests pass
• Run cargo test -p nodespace-core --lib mention_autocomplete_excludes_collection - passes
• Run cargo test -p nodespace-core --lib get_collection_by_name - passes
• Run cargo test -p nodespace-core --lib get_collections_by_names - passes
• Run full test suite - 728 passed (1 flaky test is pre-existing database lock issue)
• Run quality checks - all pass

Acceptance Criteria

• Collection nodes have title field set to content on create
• Collection nodes have title field updated when content changes
• get_collection_by_name() queries indexed title field
• get_collections_by_names() queries indexed title field
• Collections do NOT appear in @mention autocomplete results
• Existing tests pass
• Added tests for collection title sync, lookup, and @mention exclusion

Closes #844

🤖 Generated with Claude Code

[malibio]

Code Review: PR #845 - Add title field sync for collection nodes

Review Type: Initial Review

Reviewer: Principal Engineer (Pragmatic Code Review)

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Requirements Check (Issue #844)

Acceptance Criterion	Status
Collection nodes have title field set to content on create	✅ Implemented
Collection nodes have title field updated when content changes	✅ Implemented
get_collection_by_name() queries indexed title field	✅ Implemented
get_collections_by_names() queries indexed title field	✅ Implemented
MCP create_nodes_from_markdown with collection param uses indexed lookup	✅ Works via existing CollectionService.resolve_path() which calls get_collection_by_name()
Collections do NOT appear in @mention autocomplete results	✅ Implemented
Existing tests pass	✅ Verified (728 passed, 1 pre-existing flaky test)
Add tests for collection title sync, lookup, and @mention exclusion	✅ 7 comprehensive tests added

All acceptance criteria have been met.

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Code Review Findings

Architecture & Design

:large_green_circle: [Strength]: Clean, Surgical Changes

The implementation makes minimal, focused changes to achieve the goal. The hybrid approach (setting title for indexed lookup while excluding from @mention results) is elegant and maintains backwards compatibility with existing collection semantics.

Key design decisions are sound:

• Title sync happens in create_node(), create_node_with_parent(), and update_node() - covering all creation and modification paths
• Collections are explicitly filtered in mention_autocomplete() query rather than relying on implicit behavior
• Lookup queries now use indexed title instead of unindexed content

Functionality & Correctness

:large_green_circle: [Strength]: Complete Coverage of Node Lifecycle

The implementation correctly handles all code paths:

1. Direct creation via create_node() - line 1282
2. Parent-aware creation via create_node_with_parent() - lines 1463-1471
3. Updates via update_node() - lines 2116-2118

The markdown stripping (strip_markdown()) is consistently applied, matching the existing task node behavior.

:large_green_circle: [Strength]: Comprehensive Test Coverage

The test suite is thorough:

• test_collection_title_set_on_create - verifies title is set on create
• test_collection_title_updated_on_content_change - verifies title syncs on update
• test_collection_title_strips_markdown - verifies markdown stripping
• test_collection_title_via_create_node_with_parent - verifies the alternate creation path
• test_mention_autocomplete_excludes_collection_nodes - verifies @mention exclusion
• test_get_collection_by_name_uses_title_field - verifies indexed lookup
• test_get_collections_by_names_uses_title_field - verifies batch indexed lookup

Maintainability & Readability

:large_green_circle: [Strength]: Excellent Documentation

Every change includes clear issue references (#844) in comments, explaining the "why" behind the change. The docstrings for get_collection_by_name() and get_collections_by_names() were updated to reflect the new behavior.

🔸 [Nit]: Minor Comment Inconsistency

/packages/core/src/db/surreal_store.rs:2463

The comment "Issue #844: Exclude collection nodes from @mention results" appears twice - once in the preamble (line 2446-2449) and again immediately before the SQL (line 2463). The second one is redundant.

// Issue #844: Exclude collection nodes from @mention results  <-- redundant
let sql = r#"

Security

✅ No concerns. The changes are pure database query modifications with no new user input handling paths. All inputs were already validated by existing code.

Performance

:large_green_circle: [Strength]: Performance Improvement

This change converts two unindexed field queries (content) to indexed queries (title):

• get_collection_by_name(): O(n) scan -> O(log n) indexed lookup
• get_collections_by_names(): O(n) scan -> O(log n) indexed lookup

The additional node_type != 'collection' filter in mention_autocomplete() has negligible cost since it's evaluated after the indexed title filter.

Testing Strategy

✅ Excellent coverage. Tests cover:

• Happy path creation/update
• Edge cases (markdown stripping)
• Both creation APIs
• Store-level queries
• Integration behavior (@mention exclusion)

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Minor Observations (Informational)

1. CollectionNode::builder() path: The issue mentioned updating collection_node.rs to set title in to_node(). While this was NOT done, it's not a bug because:

   • All production code paths go through NodeService::create_node() which sets the title
   • The builder is primarily for tests and internal use
   • Setting title in the builder would create duplication since create_node() would overwrite it anyway

2. TODO Add title_template support for schema-driven title computation #824 references: The code references future schema-driven title_template work. These TODOs are appropriate breadcrumbs for future refactoring.

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Summary

This is a high-quality, well-tested change that:

• Improves performance for collection lookups (indexed vs unindexed)
• Correctly excludes collections from @mention results
• Maintains consistency with existing title field patterns
• Includes comprehensive tests

The code is clean, well-documented, and follows established patterns. The change is a clear net positive.

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Recommendation

✅ APPROVE

This PR is ready to merge.

[malibio]

Review Status: APPROVE (recommendation)

This PR meets all acceptance criteria and is recommended for merge. Since self-approval is not permitted, this is submitted as a comment review.

All code quality checks pass, tests are comprehensive, and the implementation follows established patterns.