feat(extraction): add Erlang language support (.erl/.hrl) (#635, #648) (#1165)

Vendored WhatsApp/tree-sitter-erlang 0.19 (the ELP grammar, ABI 14) with an
Erlang-shaped extractor: multi-clause/multi-arity functions merged into one
symbol, -spec signatures, records with fields, -type/-opaque aliases, -define
macros, -include/-include_lib file edges, and -export-driven visibility.

Modules wrap in a namespace so remote mod:fn(...) calls resolve through the
existing qualified-name matcher as mod::fn with zero resolver changes.
-behaviour declarations link to the behaviour module — gated to namespace
targets only (bare-name fallthrough linked -behaviour(supervisor) to an
unrelated macro constant on emqx). OTP indirection with static targets is
followed: spawn/apply/proc_lib/timer/rpc MFA-argument callees, and
gen_server:call/cast(?MODULE | ?SERVER) to the module's own
handle_call/handle_cast. Var-module dispatch and message sends stay
deliberately unlinked. codegraph_explore also normalizes Erlang-native query
spelling (mod:fn/3, init/2) so named symbols resolve as typed.

Benchmarked on cowboy (189 files), ejabberd (414), emqx (2,447): extraction
PASS on all three; with-codegraph arms reached 2/2/0 file Reads vs 10/5+/19
without, fastest on the largest repo.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -11,6 +11,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### New Features
 
+- CodeGraph now indexes **Erlang** (`.erl`, `.hrl`) — functions, with clauses and arities of the same name grouped as one symbol spanning all of them, plus records with their fields, `-type`/`-opaque` aliases, `-define` macros, and `-spec` signatures attached to every function. Cross-module `mod:fn(...)` calls resolve to the target module's function, `fun name/arity` values are captured as references (so callback registrations like `lists:foreach(fun submit/1, ...)` link up), `-include`/`-include_lib` connect to the header files they pull in, `-behaviour` declarations link a callback module to its behaviour (and only ever to a module — a same-named macro or function elsewhere in the repo is never mistaken for one), and `-export` lists (plus `-compile(export_all)`) drive each function's public/private flag. OTP's indirection idioms are followed where the target is static: `spawn`/`apply`/`proc_lib`/`timer`/`rpc` calls that name their target as `(Module, Function, Args)` arguments produce call edges, and a module's public API wrappers connect to its own `handle_call`/`handle_cast` when `gen_server:call`/`cast` targets `?MODULE` (including the `-define(SERVER, ?MODULE)` idiom). Truly dynamic dispatch (`Mod:handle(...)`, message sends, var-module spawns) is deliberately left unlinked rather than guessed. `codegraph_explore` also understands Erlang-native symbol spelling in queries — `mod:fn/3` and `init/2` find the symbols they name. (#635, #648)
 - CodeGraph now indexes **Visual Basic .NET** (`.vb`) — classes, Modules, interfaces, structures, enums, properties, events, `MustOverride` abstract members, and `Declare` P/Invoke signatures, with `Inherits`/`Implements` hierarchy edges, call edges (resolved through VB's ambiguous call-vs-index parentheses), and `New`/`As New` instantiation links. Real-world VB styles parse cleanly: WinForms designer files, interpolated and multi-line strings, XML literals (embedded `<%= %>` expressions included), single-line and multi-line LINQ queries, multi-line lambdas, `Handles`/`WithEvents` event wiring, Custom Events, date literals, classic type-character identifiers (`i%`, `name$`), and non-English (Unicode) identifiers. (#648, #639, #170)
 - CodeGraph now indexes **COBOL** (`.cbl`, `.cob`, `.cpy`) — programs, sections and paragraphs with `PERFORM`/`GO TO` call edges, `CALL` cross-program calls, `COPY` copybook imports (standalone copybooks included), and DATA DIVISION records with 88-level condition names, in both fixed and free source format. Impact queries work on data items: every `MOVE`/`ADD`/`COMPUTE`/`SUBTRACT` write-site links back to the field it changes, so "what touches this copybook field" answers across programs. CICS flows connect too: `EXEC CICS LINK`/`XCTL` program targets, `EXEC SQL INCLUDE` copybooks, and pseudo-conversational `RETURN TRANSID(...)` hops resolve to the program owning the transaction id. (#590, #648)
 - CodeGraph now indexes **CFML** (`.cfc`, `.cfm`, `.cfs`) — both the classic tag-based style (`<cfcomponent>`/`<cffunction>`) and modern bare-script `component { ... }` syntax, including `extends`/`implements`, embedded `<cfscript>` blocks (at any nesting depth, including inside `<cfif>`/`<cfloop>`/`<cftry>`), call edges, and calls embedded in `#hash#` expressions inside `<cfquery>` SQL bodies. Files saved with a UTF-8 byte-order mark and tags with unquoted attribute values — both common in long-lived CFML codebases — are handled too. Thanks @ghedwards. (#1118)