feat(search): field-qualified queries (kind:/lang:/path:/name:) + fuzzy typo fallback (#131)

* feat(search): field-qualified queries (kind:/lang:/path:/name:) + fuzzy typo fallback

Two UX improvements that turn a free-text search into something a
real user can drive precisely.

1) Field-qualified queries.

A new query parser (src/search/query-parser.ts) splits the raw query
into structured filters and a free-text remainder:

  kind:function name:auth path:src/api authenticate

becomes
  { kinds: ['function'], nameFilters: ['auth'],
    pathFilters: ['src/api'], text: 'authenticate' }

Filters compose with the SearchOptions arg (intersection). Unknown
prefixes pass through as plain text so `query "TODO:"` keeps working.
Quoted values (`path:"my dir"`) handle whitespace. When the user
specifies only filters with no text, the search uses a filter-only
candidate scan instead of bailing out.

Recognised today:
  kind:        any NodeKind value
  lang:        any Language value (alias: language:)
  path:        case-insensitive substring of file_path
  name:        case-insensitive substring of node.name

2) Fuzzy fallback.

When BOTH FTS and LIKE return nothing AND the text is at least 3
chars, the resolver scans the distinct-name set with a bounded
Damerau-Levenshtein-style edit distance (≤2 for ≥5 chars, ≤1 for
4-char queries, off for shorter). Bounded edit-distance early-exits
once the row min exceeds maxDist, so this stays O(distinct-names *
avg-name-length) with a very low constant.

Verified live against ollama/ollama@v0.22.0:
  query "kind:function auth"          → only function-kind hits
  query "lang:go path:server route"   → Go files under server/
  query "getUssr"   (typo)            → finds getUser, SetUser
  query "confg"     (typo)            → finds Config

Full test suite: 380 passed.

* fix(search): address reviewer findings — tokenizer mid-token quotes, fuzzy fan-out cap, larger filter-only over-fetch, unit tests

Five fixes from independent review:

- parseQuery tokenizer: quotes that appear MID-token (path:"my dir/
  file") were not being recognised — only quotes at the start of a
  token were treated as quoted spans. The fixture path:"my dir"
  parsed as ['path:"my', 'dir"'] instead of ['path:"my dir"'].
  Tokeniser is now a single state machine that scans into a token
  until whitespace OR a quote, and recognises quotes anywhere within
  the token (skips to the matching close quote).

- searchNodesFuzzy: cap the per-name follow-up SQL queries at
  Math.max(limit*2, 50) AFTER edit-distance filtering. Without
  this, a project with many similar names (getUser1, getUser2...)
  could fan out far beyond limit queries before the inner-loop
  break kicks in.

- searchAllByFilters (filter-only no-text path): bumped over-fetch
  multiplier from 2× to 5× so a selective post-filter (e.g.
  path:src/very/specific/file.ts) doesn't return fewer than limit
  results despite the DB having matches.

- 23 new unit tests in __tests__/search-query-parser.test.ts:
  parseQuery covers known-field filter, lang/language alias,
  multiple kind: ORs, quoted spans (incl. mid-token), URL
  passthrough, empty-value passthrough, unknown prefix passthrough,
  unknown value passthrough, all-filters-no-text, empty input,
  20k-char input. boundedEditDistance covers identity, single
  insertion/deletion/substitution, length-difference shortcut,
  empty inputs, case-sensitivity, early-exit correctness.

Full test suite: 853 passed (up from 830).

* refactor(search): derive parser kind/lang sets from types.ts as const

Convert NodeKind and Language to runtime-iterable as const arrays
(NODE_KINDS, LANGUAGES) so the query parser imports the canonical
list instead of duplicating it. Also fix the path: JSDoc to say
substring (matches the .includes() impl).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Colby McHenry <me@colbymchenry.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/types.ts

@@ -9,31 +9,38 @@
 // =============================================================================
 
 /**
- * Types of nodes in the knowledge graph
+ * Types of nodes in the knowledge graph.
+ *
+ * Defined as a runtime-iterable `as const` array so the same source
+ * of truth backs both the TS type and any runtime validation
+ * (e.g. the search query parser).
  */
-export type NodeKind =
-  | 'file'
-  | 'module'
-  | 'class'
-  | 'struct'
-  | 'interface'
-  | 'trait'
-  | 'protocol'
-  | 'function'
-  | 'method'
-  | 'property'
-  | 'field'
-  | 'variable'
-  | 'constant'
-  | 'enum'
-  | 'enum_member'
-  | 'type_alias'
-  | 'namespace'
-  | 'parameter'
-  | 'import'
-  | 'export'
-  | 'route'
-  | 'component';
+export const NODE_KINDS = [
+  'file',
+  'module',
+  'class',
+  'struct',
+  'interface',
+  'trait',
+  'protocol',
+  'function',
+  'method',
+  'property',
+  'field',
+  'variable',
+  'constant',
+  'enum',
+  'enum_member',
+  'type_alias',
+  'namespace',
+  'parameter',
+  'import',
+  'export',
+  'route',
+  'component',
+] as const;
+
+export type NodeKind = (typeof NODE_KINDS)[number];
 
 /**
  * Types of edges (relationships) between nodes
@@ -53,29 +60,33 @@ export type EdgeKind =
   | 'decorates';      // Decorator applied to symbol
 
 /**
- * Supported programming languages
+ * Supported programming languages. See NODE_KINDS for why this is a
+ * runtime-iterable const array.
  */
-export type Language =
-  | 'typescript'
-  | 'javascript'
-  | 'tsx'
-  | 'jsx'
-  | 'python'
-  | 'go'
-  | 'rust'
-  | 'java'
-  | 'c'
-  | 'cpp'
-  | 'csharp'
-  | 'php'
-  | 'ruby'
-  | 'swift'
-  | 'kotlin'
-  | 'dart'
-  | 'svelte'
-  | 'liquid'
-  | 'pascal'
-  | 'unknown';
+export const LANGUAGES = [
+  'typescript',
+  'javascript',
+  'tsx',
+  'jsx',
+  'python',
+  'go',
+  'rust',
+  'java',
+  'c',
+  'cpp',
+  'csharp',
+  'php',
+  'ruby',
+  'swift',
+  'kotlin',
+  'dart',
+  'svelte',
+  'liquid',
+  'pascal',
+  'unknown',
+] as const;
+
+export type Language = (typeof LANGUAGES)[number];
 
 // =============================================================================
 // Core Graph Types