feat(coding-agent): generate the session-cwd surface via fluessig

[zmaril]

Swap the hand-written #[napi] session-cwd exports (coding-agent core/session-cwd.ts) to the fluessig-generated path.

Module 12 of the pidgin-napi → fluessig campaign (module 2 of this stacked batch of 3). Stacked on napi-fluessig/strip-ansi (#322).

What changed

• Author 3 ops + the SessionCwdIssueJs DTO in schema/api.json.
• Add the 3 core_impl delegations (DTO conversions + SessionCwdSource adapter) reaching the same pidgin_coding::core::session_cwd port the hand-written exports called.
• Regenerate src/generated.rs; delete src/session_cwd.rs and drop pub mod session_cwd;.

First DTO-both-directions swap

SessionCwdIssueJs is a fluessig model used as a nullable return (getMissingSessionCwdIssue -> SessionCwdIssueJs | null), a by-value param (both formatters take issue: SessionCwdIssueJs), and carries an optional field (sessionFile?: string). fluessig lowers Option<Model> return, Model param, and the nullable model field (Option<String>) with no gap.

Gates

• Byte-diff vs a pre-swap build of the base: the SessionCwdIssueJs interface (sessionFile?: string) and all three function JSDoc+signature blocks, their .js module.exports lines, and nativeBinding destructure entries are byte-identical (only file position moves into the generated cluster).
• cargo build -p pidgin-napi, cargo fmt --all --check, cargo clippy -p pidgin-napi --all-targets -- -D warnings clean; codespell 0.
• straitjacket v0.2.3: 0 errors.
• Oracle slice coding-agent/test/session-cwd.test.ts: 3/3 pass against the locally-built generated addon.

🤖 Generated with Claude Code

https://claude.ai/code/session_017xL2W7dkhPsTSRuXQNCDeY

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Generated by Claude Code

[github-actions]

Conformance smoke: agent + ai + tui

• pi_sha: 3da591ab74ab9ab407e72ed882600b2c851fae21
• manifest_native_modules: 45

Headline is rust-backed: passing cases in files whose module-under-test is a native (Rust addon) module. Raw all-pass is shown secondary — it is inflated by unflipped TypeScript that passes without touching any Rust.

Package	rust-backed	Native modules	raw pass (secondary)	Failing	Skipped
agent	55/180 (30.6%)	5	180/180	0	0
ai	74/1293 (5.7%)	8	553/1293	3	737
tui	375/678 (55.3%)	14	678/678	0	0
smoke total	504/2151 (23.4%)	27	1411/2151	3	737

agent: 55/180 (30.6%) · ai: 74/1293 (5.7%) · tui: 375/678 (55.3%)

rust-backed = passing / total tests run, per the manifest's per-native-row tests lists. The Native modules column counts modules served by the Rust addon. This is the agent+ai+tui smoke subset; the full baseline lives in committed conformance.json.

Attribution

A pi test file is rust-backed iff the module it primarily exercises — its module-under-test — is status=native in conformance/manifest.json. A package's rust-backed count is the passing cases in its rust-backed files. Transitive or infrastructure use does not count (e.g. ~30 ai files construct the native faux provider but test other things — only faux-provider.test.ts, whose subject is faux, counts). A file that substantially tests both a native and an original module is excluded rather than counted, so the number under-reports rather than over-claims.

Per-file decisions (from each native manifest row's tests list):

Native module	Test file	Decision
ai/api/anthropic-messages.ts	test/anthropic-sse-parsing.test.ts	counted
ai/providers/faux.ts	test/faux-provider.test.ts	counted
coding-agent/utils/ansi.ts	test/ansi-utils.test.ts	counted
coding-agent/utils/changelog.ts	test/changelog.test.ts	counted
coding-agent/utils/git.ts	test/git-ssh-url.test.ts	counted
coding-agent/core/tools/path-utils.ts	test/path-utils.test.ts	counted
tui/keys.ts	test/keys.test.ts	counted
tui/utils.ts	test/truncate-to-width.test.ts, test/regression-regional-indicator-width.test.ts	counted
coding-agent/utils/mime.ts	test/image-process.test.ts	mixed — excluded (2 of 3 cases test processImage/original)
coding-agent/utils/version-check.ts	test/version-check.test.ts	mixed — excluded (fetch cases mock the original; not separable per-file)
coding-agent/core/export-html/ansi-to-html.ts	test/export-html-whitespace.test.ts	mixed — excluded (asset-grep + tool-renderer/original dominate)
coding-agent/core/tools/truncate.ts	—	no dedicated test (exercised via tools.test.ts, subject is the read/edit factory/original)
coding-agent/core/tools/edit-diff.ts	—	no dedicated test (edit-tool tests' subject is the edit tool/original)

CLI conformance (black-box, against the pidgin binary)

• CLI conformance: 15/15 pass against target/release/pidgin (pass delta ±0, fail delta ±0).

File	Passing	Failing	Skipped
packages/coding-agent/test/session-file-invalid.test.ts	1	0	0
packages/coding-agent/test/session-id-readonly.test.ts	7	0	0
packages/coding-agent/test/startup-session-name.test.ts	2	0	0
packages/coding-agent/test/stdout-cleanliness.test.ts	5	0	0

The four repointed coding-agent CLI test files spawn the compiled pidgin binary via $PIDGIN_BIN instead of pi's own cli.ts. This is a separate signal from the module smoke table and is never folded into the per-package Native count.