feat(parsers): add Swift and Objective-C language support

[tob-scott-a]

Two new parsers using tree-sitter-language-pack's swift and objc grammars, which are already installed as transitive dependencies so this lands with no new direct deps.

Swift (.swift):

• top-level functions, classes, structs, enums, protocols, extensions
• methods (with parent class/struct/protocol as container)
• parameter and return-type capture via user_type / type_identifier
• import declarations captured as graph.dependencies
• cyclomatic complexity from if/guard/for/while/switch/do/catch
• @main entrypoint detection

Known gap: Swift throw statements use control_transfer_statement,
which collides with return/break/continue. Capturing throws requires a
Swift-specific walk that filters by throw_keyword — deferred with a
test that locks in non-crash behavior for now.

Objective-C (.m, .mm, .h):

• top-level C functions (covers main, helper functions)
• @interface / @implementation classes
• method signatures from @interface and bodies from @implementation (implementation replaces any earlier stub)
• selector-based method naming — login:password: preserves both keywords so overloads with different argument labels don't collide
• #import / #include captured as dependencies
• UIApplicationDelegate lifecycle selectors flagged as untrusted external API (deep-link handlers, launch callbacks)

Cross-language plumbing:

• extract_call_name gains a fallback path for grammars that don't label the callable (Swift emits call_expression with an unlabelled first child).
• _CALL_NAME_TYPES adds simple_identifier and navigation_expression for Swift callables.