docs: record the documentation pass in the 1.0.0 changelog

Six commits landed after the 1.0.0 section was written, and none of them
appear in it. The release was never tagged or pushed, so they belong in
that section rather than in a 1.0.1 for changes no one could have run:
version.go stays at 1.0.0. This is the same call bde9a2e made for 0.16.0.

They are worth recording rather than dropping as "docs only". README.md
ships inside every release archive, and its gosentry.json sample — the one
file the user is invited to hand-edit — was wrong until this pass. The
rest is the contributor documentation catching up with the code it
describes: TESTS.md indexing 130 of 170 tests, ARCHITECTURE drawing an
edge the UI does not have, and the file-length guideline stated as settled
while six files are over it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/CHANGELOG.md

@@ -52,6 +52,38 @@ dragged.**
   row's edge — does not, so the gap collapsed to about a pixel. The Theme row
   now keeps the same gap the checkbox rows have.
 
+**Documentation:**
+
+- The **README** describes the application that exists. Its `gosentry.json`
+  sample was three keys short of what the app writes on first run, which made
+  the one file the user is invited to hand-edit the least accurate thing in the
+  document; it is now the real default, with each key explained — including why
+  a zero timeout is written out and an unset one is not. The feature list has
+  caught up with the run timeout, the theme, the compact job list, and the
+  per-job overlap and timeout overrides the job dialog has always offered.
+- **`docs/DEVELOPMENT.md`** is ordered as stack, external libraries, run from
+  source, build, release, CI, behind a two-level table of contents, instead of
+  opening with MSYS2 setup and burying "Run From Source" mid-document. The
+  library table gains versions and licenses, the `package-*` scripts are
+  documented for the first time and labelled by OS, and the Codeberg
+  `RELEASE_TOKEN` note now states the failure mode rather than leaving it to be
+  inferred from a red job: build and packaging succeed, the upload step fails on
+  authentication and takes the job with it, leaving a published release with no
+  assets. The Project Layout section is gone — it duplicated ARCHITECTURE's
+  package map and had drifted out of date.
+- **`docs/TESTS.md`** matches the suite it indexes again. It listed 130 tests
+  against 170 in the tree, omitted four test files entirely, and named two tests
+  that no longer exist. Every test function now appears exactly once, under the
+  file it actually lives in.
+- **`docs/ARCHITECTURE.md`** no longer draws the UI calling the autostart
+  manager directly — it does not, and `src/ui` holds no reference to that
+  package — and `platform/desktop` is described by what it does (the XDG desktop
+  entry and icon) rather than as a display-scale helper.
+- The **~250-line file guideline** is stated as the target it is, with the six
+  files currently over it recorded as a `docs/ROADMAP.md` item. They are to be
+  split in one pass during the next whole-project review, since six separate
+  passes would settle the same seam question six ways.
+
 ## 0.15.0 - 2026-07-26
 
 **Settings points at the jobs file itself, not the folder holding it.**