docs(standard): admin tier defined; promises require owner approval

Two additions to the screenshot-free writing standard, both owner-
ruled during the admin-docs planning session:

- Tone by audience gains the Administration tier, ending the 'not yet
  decided' limbo for admin docs: plain language like the user docs, plus
  what every control actually does (semantics, cost, consequences)
  before the reader clicks, and per-setting what/does/means/range
  coverage. Calibration in one line: user = what you see, admin = what
  it does, developer = how it works. The Developer section keeps its
  separate tone discussion for the deferred dev-docs pass.

- New 'Promises need approval' section: no coming-soon / under-
  consideration / future-release language anywhere without the owner's
  explicit approval of that exact promise; speculative text found in the
  docs is reported, never quietly kept or quietly deleted. Provenance
  recorded (the 2026-11-02 device-promise removals; the Operations
  placeholders knowingly kept).

docs/developer/writing-ui-docs.md

@@ -74,9 +74,21 @@ make the page followable even if that label is renamed next week.
   genuinely needs (say, *rule*) is explained once, in place, then used
   consistently. The reader is assumed to know books, while the app's own
   words are the only technical vocabulary allowed.
-- **Developer and Administration sections — tone is a separate discussion,
-  not yet decided.** Write them plainly and hand-off-rich as well; do not
-  import opinions about their voice until that pass happens.
+- **Administration (`docs/admin/`) — plain language, one layer deeper.**
+  Same bones as the user docs: task-first, what to click for what, exact
+  quoted labels. Added: every control also states what the click *actually
+  does* — semantics, cost, and consequences — before the reader clicks it.
+  The canonical example: **Force Rescan All Libraries** re-reads and
+  re-extracts every file and recomputes hashes, while the other scan
+  buttons are shallow scans that skip unchanged files — an admin should
+  know that before clicking, not after. Every setting states what it is,
+  what it does, what it means when that is confusing, and its valid range.
+  No API-client detail: request and response schemas live in the developer
+  docs. The calibration in one line: **user = what you see, admin = what
+  it does, developer = how it works.**
+- **Developer section — tone is a separate discussion, not yet decided.**
+  Write it plainly and hand-off-rich as well; do not import opinions about
+  its voice until that pass happens.
 
 ## Generate what has a registry
 
@@ -109,6 +121,18 @@ resolve, links still resolve, affected pages re-read against the new
 surface. The pattern layers keep users oriented between audits; the audit
 keeps layers 3–5 honest.
 
+## Promises need approval
+
+Docs never promise future behavior on the owner's behalf. No "coming soon",
+"under consideration", "in a future release", or any other forward-looking
+commitment gets written without the owner explicitly approving that exact
+promise — and anything speculative found in the docs gets reported, not
+quietly kept and not quietly deleted. (Rule origin, 2026-11-02: the owner
+ruled out "Kindle and reMarkable are under consideration" and a "Custom
+Calibre Columns (Future)" section — no such plans existed — while the
+Operations guide's pre-existing "Coming Soon" placeholders were reported
+and knowingly kept for the future operations-docs pass.)
+
 ## What this does not replace
 
 The filter documentation (and the older filtering overview) is hands-off