`src/preload/api-types.ts` was 3,752 raw lines (3,533 counted, 11.8x the
300-line budget) behind an `eslint-disable max-lines`. Almost all of it was a
single `PreloadApi` object type whose ~83 namespace properties were declared
inline, so any IPC surface change meant editing one 2,600-line type.
Give each namespace a named type in its own module under `src/preload/api/`
(`pty-api.ts`, `filesystem-api.ts`, `github-pull-request-api.ts`, ...) and
recompose `PreloadApi` from those names. `api-types.ts` keeps the `declare
global` Window augmentation and re-exports every moved name, so all 52 import
sites are untouched.
Two shapes needed care to stay type-identical rather than merely compatible:
- Three keys (`gh`, `git`, `ui`) are composed from two modules each. A plain
intersection is NOT identical to the original flat object literal, so those
use a `Merged<T>` mapped type; a negative control confirmed that dropping it
fails the parity assertion.
- Keys whose module groups several namespaces use indexed access
(`fs: FilesystemApi['fs']`) to preserve exact identity and source order.
`config/tsconfig.web.json` and `tsconfig.tc.web.json` enumerate files by path,
so they need `src/preload/api/**/*` alongside the existing `api-types.ts` seed
or the web projects fail TS6307.
Verified by exact type identity, not assignability: 41 assertions of the form
`Equals<Now.X, Before.X>` against a frozen pre-split snapshot, covering every
exported name, plus a per-key pass over all 83 `PreloadApi` keys. All three
projects typecheck clean with those assertions active.
Verification note: these tsconfigs are `composite: true`, and `tsc --noEmit`
will reuse a stale `.tsbuildinfo` and report clean for a state that genuinely
fails. Every result above was produced after deleting the buildinfo, including
a negative control confirming the gate still fails on deliberate drift.
Drops the `max-lines` bypass and its baseline entry (ratchet 346 -> 345).
