Draw a model's thinking, and what a reply cost to produce

A llama.cpp session's `reasoning_content` becomes `Event::Thinking` deltas
closed by an `Event::ThinkingDone` carrying the span the driver measured, and
the phone draws it as a card of its own: "Thinking" with the spinner a running
command has, then "Thought for 12.4s". Deliberately not a tool call, so a run
of calls cannot collapse the reasoning into "Called 6 tools"; the reasoning is
also kept out of the next prompt, which `conversation` already ignored.

`UsageDelta` gains `tokensPerSecond`, the provider's own figure or nothing --
llama.cpp reports `timings.predicted_per_second` and the coding CLIs report no
such thing -- and a finished reply carries a small line under it saying when it
was sent and, where there is one, how fast it came out: "3:00 PM · 149 tok/s".

The compact usage bar drops the provider's name for the window and puts its
length after the time left instead: "42% · 3h 20m left / 5h".

Three things that had to come with it: the transcript coalesces runs of
thinking deltas as it does reply deltas, so one block is one row of a page
rather than a page of its own; `joinPages` welds a block cut by a page boundary
(`healSplitThinking`), since the half with no ending spun for ever; and
`UsageDelta` now reaches the fold, which is what carries the rate to the reply.

Verified on the emulator against a real Qwen3-0.6B session and the echo rig's
new `/think [seconds]`: the spinner while it runs, "Thought for 1.4s" and
"2:54 PM · 149 tok/s" after, the reasoning on tapping the card, and the usage
bar reading "42% · 3h 19m left / 5h".

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

.claude/skills/ai-app-rigs/SKILL.md

@@ -81,6 +81,10 @@ Each exists because something was invisible without it.
   `debug-transcript.sh` when it is *what the transcript draws*. The sandbox's
   version also handles `auth login`: it prints an inert Anthropic-shaped URL,
   rejects any code except `sandbox-code`, and exits successfully for that one.
+- **`/think [seconds]` in an echo session puts up a thinking card**, long
+  enough to watch it spin before it closes with the span it actually took.
+  The rest of the turn is the ordinary echo reply, so it is also the rig for
+  a block and a reply meeting.
 - **`app/transcript-bench.sh`** is the standard scroll measurement: it opens
   the first session (or `-k` keeps the current screen), scrolls a fixed
   gesture loop, and prints the app's render report — the same one the in-app