v0.5.2: The withheld criteria could reach the coding agent six more ways, all closed, and a run that stops when you stop it

Fixed

• Six further ways the acceptance criteria could reach the coding agent, all
  found by audit and all confirmed by running before being believed. A YAML
  merge key (<<:) pulling criteria in from an anchor, which left the file
  entirely unstripped. An alias whose anchor lives under another key, so the
  reference went and the content stayed. Two acceptance_criteria: keys, where
  the parser takes the last and the strip removed the first. A second copy
  nested under an unrelated key. Criteria written as a mapping rather than a
  list, which the verification collected as nothing at all. And a requirement
  short enough to blind the check meant to exempt it.

  One cause behind all of them: yaml.safe_load decides what the criteria are,
  because it is what test generation reads, and every other idea of where they
  live is a second opinion that can differ. The strip now removes the span YAML
  itself assigns the key, then verifies by collecting every criterion the
  parser sees, at any depth and whatever shape holds it, parsing the handed-over
  text back, and comparing values to values with whitespace and Unicode
  normalised. A file it cannot prove clean is refused rather than handed
  over, naming the construction so its author can fix it. No bundled task,
  and no file the scaffolder writes, is affected.

• Ctrl+C now stops the run it says it stopped. terminate() reaches the
  task process and not the pytest it is blocked inside, so a test runner
  supervised by nobody kept writing to the iteration log after the console said
  "Stopped". The whole tree goes now, and the ordering is the fix: taken after
  the task exits, its children have been reparented and there is nothing left
  to walk from.

• A generated test that reads a name before assigning it is regenerated
  rather than run. records = transform(records) raises NameError every
  time, so the coding agent sees an identical failure each iteration with
  nothing to act on and spends its whole budget on a file whose problem is not
  in its code. Measured on the worked example: every failure in 50 runs was a
  test of this shape, and the check flags 4 files in 1426 real generated ones.

• The repeated sweep only ever ran from a git clone, so a sweep started
  from an installed copy failed once per task per repetition with no model
  call. Its own accounting is what caught it, refusing to quote a rate computed
  over zero runs.

Changed

• The update notice says how to upgrade. pip install qikly on an existing
  install prints "Requirement already satisfied" and changes nothing, so a
  reader could follow the notice, type the obvious command, and stay where they
  were. It now names pip install --upgrade qikly.
• An aggregate says when the runs it pooled were not the same experiment,
  comparing the model, the provider, both budgets, the feedback settings, the
  version and the commit that produced each one, and saying when a field is
  missing from some of them rather than treating absent as agreeing.
• PRIVACY.md now names the Jira fetch and the User-Agent the version
  check sends.

Measured

• Convergence held while the bar was tightened, which is the claim worth
  making: 80% of runs pass every integration and system test and 60% pass
  everything, over 130 runs on this release and 520 across 0.5.x, unchanged
  from the 967 runs measured before any of this hardening existed.