bump codeanalyzer-typescript pin to 1.6.1

[rahlk]

Is your feature request related to a problem? Please describe.

pyproject.toml hard-pins the TypeScript analyzer:

dependencies = [ ..., "codeanalyzer-typescript==1.5.3", ... ]

[tool.backend-versions]
codeanalyzer-typescript = "1.5.3"

Two analyzer releases have shipped past that pin — 1.6.0 (Neo4j projection gained source on :TSModule and four span properties across ten node labels, codellm-devkit/codeanalyzer-typescript#201) and 1.6.1 (shipped entrypoint rules for Remix, Astro and the Next.js src/ layout, plus two handler-resolution fixes, codellm-devkit/codeanalyzer-typescript#206). Neither reaches a single SDK user until this pin moves: an analyzer release and a consumable analyzer release are two different claims, and the pin is the gate between them.

Describe the solution you'd like

• dependencies pin → codeanalyzer-typescript==1.6.1.
• [tool.backend-versions] table → 1.6.1 (both must move together; they are read independently).
• E2E suite green against the 1.6.1 binary — pytest tests/test_typescript_e2e.py with the binary on PATH, not skipped.

Describe alternatives you've considered

Not stated in the original issue.

Additional context

Scope boundary

• Pin bump only, in both places the version appears. No facade change, no new accessor.
• Neither analyzer release moved the schema contract: SCHEMA_VERSION is unchanged and 1.6.1's schema.neo4j.json is byte-identical to 1.6.0's. Consumers detect the additions by presence.
• Whether the SDK cuts its own release after this is a separate decision, not part of this issue.

Caveats and known risks

• 1.6.1's entrypoint changes mean entrypoints[] is non-empty in fixtures where it was previously empty for any project using Remix, Astro or Next.js src/ layout, and callables previously counted in entrypoint_report.unresolved now carry records. Any SDK test asserting an exact entrypoint count or an exact unresolved map on such a fixture will fail, and that failure is correct — check before treating it as a regression.
• 1.6.0 added Neo4j node properties. An SDK assertion enumerating a node's exact property set (rather than checking membership) will fail for the same reason.

Definition of done

Both pins read 1.6.1, the mocked/E2E/backend-contract tiers are green with the 1.6.1 binary actually installed, and any fixture expectation that changed is updated with a comment naming which analyzer release changed it.