fix: hook error sanitize/dedup + abort trailer tool-call mention + token parity - #66

…t tool count + token parity (dirge-code#66)

TDD: tests first, all 6 new tests failed initially, then implemented.

## Round A — hook error sanitize + dedup

Two bugs in PR dirge-code#64's hook-error notification path:

1. Multi-line / tab-containing Janet errors broke the
   `level\tmsg\n` wire format. A `(error "trace\n  at file:42")`
   produced multiple malformed notification entries (one per source
   line), the first with truncated content and the rest filtered
   out as malformed. drain_notifications splits raw on `\n` per
   entry and on first `\t` per level/msg — both control chars now
   sanitized in Janet before push.

2. A buggy `on-message-update` hook (fires ~every 16 streamed
   tokens) flooded the chat with thousands of identical "[plugin]
   hook X.Y errored: ..." banners during a single long response.
   Now deduped: two new Janet vars track the most-recent sanitized
   error msg + a consecutive-repeat count; identical errors just
   bump the count instead of pushing. On drain, any outstanding
   count is flushed as a "(repeated N times)" summary entry.

Implementation:
- `harness/sanitize-hook-err` (new) normalizes `\t` → space and
  `\n`/`\r\n` → ` | `. Distinct hook errors stay separate; only
  consecutive identical ones collapse. Wrote with explicit nested
  `string/replace-all` calls — Janet's `->` threading macro
  would pass the string in the wrong arg position
  (string/replace-all expects `(patt subst str)`).
- `harness/push-hook-err` (new) does the dedup check using
  `harness-last-hook-err-msg` + `harness-last-hook-err-count`
  module-level vars.
- `drain_notifications` flushes pending dedup count before reading
  the notif list so a 50× repeat shows up as a single
  "(repeated 50 times)" entry in the next drain.
- The catch arm in `dispatch` calls these instead of appending
  directly. Wrapped in explicit `(do ...)` for Janet's
  single-form catch-body semantics.

## Round B — partial-on-abort trailer notes tool calls

PR dirge-code#65 saved the streamed assistant text on abort but didn't
indicate that tool calls had also run in the same turn (whose
results aren't in `response_buf` — only Token events accumulate
there). The LLM on next turn would see the partial as a definitive
"this was my reply" and could re-run side-effecting tools.

`capture_partial_on_abort` now takes a `tool_calls_in_turn: u32`
parameter. When non-zero, the trailer reads:
  [interrupted by user (Ctrl+C); 2 tool calls ran in this turn — results not preserved]
Singular case ("1 tool call ran") uses the right noun.

UI loop tracks `tool_calls_this_run: u32`, incremented on every
`AgentEvent::ToolCall`, reset on `Done`/`Interjected`/both abort
sites (since each marks the end of one agent run).

## Round C — token-accumulator parity on abort

`Done` and `Interjected` branches both update `session.total_tokens`
alongside the message add. The abort path didn't — made aborted
turns look like zero-token contributions in the placeholder
field. Fixed with an explicit
`session.total_tokens.saturating_add(Session::estimate_tokens(&stashed))`
inside `capture_partial_on_abort`.

Both fields stay under the `TODO(cost-tracking)` comment but at
least they're now internally consistent.

## Test plan

- [x] 6 new tests (3 plugin dispatch + 3 capture_partial_on_abort
      + 2 updated existing tests with new signature).
- [x] `cargo test --features plugin` -> 622 pass, 0 fail.
- [x] `cargo build --all-features` -> compiles.

## Skipped (observational, not bugs)

- #3 print/loop mode notifications never drained: print mode is
  non-interactive; tracing::warn (via `--verbose`) is the right
  channel.
- #4 Janet `err` non-string-coerced: `(string ...)` calls Janet's
  `tostring` which handles any value type. Documented behavior.
- dirge-code#7 markdown rendering of `[interrupted by user (Ctrl+C)]`: not
  a link by pulldown-cmark's rules; visually acceptable inline.

Co-authored-by: Yogthos <yogthos@gmail.com>