…ense (#2…"

This reverts commit 9843adb.

Two regressions from 8c0a1b2 that fail markdownlint and would block CI:

- MD009: trailing space after the new getting-started link
- MD051: stale '#2-configure-an-llm-provider' fragment in the testing
  section now that the experiment step is removed and Configure an LLM
  provider is step 1

> Coder Agent generated this commit on @david-fraley's behalf.

… history

Replaces the previous draft of this PR (a backend workspaces.claimed_at
column plus migration plus SDK plumbing) with a frontend-only
heuristic per Cian's review.

The /agents archive-and-delete molly-guard previously compared
workspace.created_at against chat.created_at to decide whether to
require typing the workspace name. ClaimPrebuiltWorkspace never
updates workspace.created_at, so claimed prebuilds always looked
pre-existing and the dialog misfired.

Build history already records the truth: build #1's initiator is the
prebuilds system user iff the workspace was a prebuild, and build #2
is the claim. Compute that in the resolver and compare its created_at
against the chat. From-scratch workspaces fall through to
workspace.created_at as before.

The prebuilds system user UUID is hardcoded on the frontend; it lives
in coderd/database/constants.go on the backend and has not changed
since the prebuild feature shipped. If it ever moves, both sides have
to move together.

🤖 Generated with the help of Coder Agents.

Co-authored-by: Ben Potter <ben@coder.com>

waitForTaskIdle used time.NewTicker(5s) which delays the first poll
by 5 seconds. Debugger tracing proved the failure mechanism: on slow
CI (Windows), the first poll at 5s sees "working" (idle patch has not
landed due to goroutine scheduling), needs poll #2 at 10s, but the
25s context expires before it fires.

Two changes:

1. Use r.clock.NewTicker (quartz) with time.Nanosecond initial
   interval and Reset(5s) for immediate first poll. Tests inject a
   mock clock via clitest.NewWithClock for deterministic control.
2. Rewrite WaitsForWorkingAppState test with quartz traps
   (NewTicker + TickerReset) for deterministic synchronization
   instead of racing goroutines. Fix PausedDuringWaitForReady
   sync point.

Closes https://linear.app/codercom/issue/DEVEX-381

waitForTaskIdle used time.NewTicker(5s) which delays the first poll
by 5 seconds. Debugger tracing proved the failure mechanism: on slow
CI (Windows), the first poll at 5s sees "working" (idle patch has not
landed due to goroutine scheduling), needs poll #2 at 10s, but the
25s context expires before it fires.

Two changes:

1. Use r.clock.NewTicker (quartz) with time.Nanosecond initial
   interval and Reset(5s) for immediate first poll. Tests inject a
   mock clock via clitest.NewWithClock for deterministic control.
2. Rewrite WaitsForWorkingAppState test with quartz traps
   (NewTicker + TickerReset) for deterministic synchronization
   instead of racing goroutines. Fix PausedDuringWaitForReady
   sync point.

Closes https://linear.app/codercom/issue/DEVEX-381

#25648)

waitForTaskIdle used time.NewTicker(5s) which delays the first poll
by 5 seconds. Debugger tracing proved the failure mechanism: on slow
CI (Windows), the first poll at 5s sees "working" (idle patch has not
landed due to goroutine scheduling), needs poll #2 at 10s, but the
25s context expires before it fires.

Two changes:

1. Use r.clock.NewTicker (quartz) with time.Nanosecond initial
   interval and Reset(5s) for immediate first poll. Tests inject a
   mock clock via clitest.NewWithClock for deterministic control.
2. Rewrite WaitsForWorkingAppState test with quartz traps
   (NewTicker + TickerReset) for deterministic synchronization
   instead of racing goroutines. Fix PausedDuringWaitForReady
   sync point.

Closes DEVEX-381

…PR tab for demo

Hardcodes 'fix: increase icon sizes for wcag 2.2 compliance' (PR #2
from coder-ux-prototypes) as a second PR tab in the dropdown to
demonstrate multi-PR switching UI. The extra tab reuses the remote
diff content panel.