crucible 0.0.3

Configuration files. Everything crucible could only be told on the command line
or through the environment can now be written down.

Added

• Configuration in JSON, read from three files, nearest to the work last:

  ~/.crucible/config.json          yours, everywhere
  .crucible/config.json            this project's, checked in
  .crucible/config.local.json      this project's, yours alone
  

  A scalar takes the nearest layer that set it; an object is merged key by key,
  so a project naming one provider leaves your other one alone. The command line
  is nearer than all three. Every file is optional and a machine with none of
  them behaves exactly as before.

  Three blocks: providers, keyed by provider name, each taking a model and
  an apiKeyEnv; env, the variables the commands crucible runs are given; and
  output, holding color and toolDetail. See
  docs/configuration.md.

• apiKeyEnv, which points a provider at a different environment variable —
  what a second key for the same vendor needs. It takes a variable name, and a
  key still has no path into a file crucible reads or writes.

• A checked-in file may not set an arbitrary env variable. Anything in
  .crucible/config.json reaches everyone who clones the repository, so a name
  that is not crucible's own is refused there and pointed at
  .crucible/config.local.json instead. crucible's own names — the
  CRUCIBLE_CODE_ prefix — are allowed, because those are knobs this program
  declares rather than somewhere a secret could hide. The refusal is structural
  and there is no setting that turns it off.

• A JSON schema, at
  schema/crucible-code-schema.json. Adding
  "$schema": "https://www.schemastore.org/crucible-code-schema.json" to a
  file gets completion, validation and a sentence about each key from your
  editor. It is generated from the same declaration the parser walks and a gate
  compares it against the checked-in copy, so an editor that accepts a document
  and a crucible that refuses it would have to disagree with itself.

• Refusals written for somebody with the file open. A rejected document
  names the file, the dotted path, the line and column, and what was accepted
  instead — and where a key appears more than once it gives no position rather
  than a plausible wrong one:

  crucible: /home/you/api/.crucible/config.json: output.colour is not a setting
  crucible has at line 3, column 5 — accepted here: color, toolDetail
  

Changed

• crucible keeps its own files in ~/.crucible/ — the configuration file
  and the session logs together. Sessions used to live under
  $XDG_DATA_HOME/crucible/sessions, which means nothing on Windows and is the
  wrong place on macOS.

  Nothing is moved for you. A sessions directory already at the old path
  keeps being used, so --continue still finds the work you were in the middle
  of; the new location is taken only by a machine that has neither.
  docs/sessions.md says how to move it by hand if you want
  it moved.

  CRUCIBLE_CODE_HOME relocates the whole directory, as an absolute path, and
  turns off looking at the old tree. Because it is read to find the
  configuration file, it is the one setting of crucible's own that a
  configuration file cannot carry — writing it in one is refused rather than
  accepted and quietly ignored.

• --model is optional and takes a bare provider. crucible --model openai/ names the provider and leaves the model to providers.openai.model;
  crucible on its own does the same for Anthropic. With nothing configured
  either way the model is still claude-sonnet-5.