feat(services): price identification by actual items identified

[zoeyrose]

Outcome

Replace Smith identification's flat NPC-level fee with a bounded work-based
quote and actual-work settlement. The player sees what inventory scope will be
examined and an exact or ranged price; after confirmation, the amount charged
is based on the number of items actually identified. A no-op costs nothing.

This is a future content consumer of
atrinik/classic#264. It is
related to temple service design in #106 but does not block that temple-specific
delivery.

Current behavior

Smith.py
currently prices mass identification as 200 + 50 * NPC level and one marked
item as 50 + 10 * NPC level, regardless of how many eligible items can be
identified.

On confirmation it removes the full fee before calling
CastIdentify().
The script only rejects a missing marked object for the single-item service; it
does not know whether the marked item is already identified, too difficult, or
otherwise ineligible, nor how many objects mass identification actually
changes.

Proposed behavior

• Query Classic for bounded items_identified work in the exact marked,
  marked-container, or normal inventory scope.
• Convert the work count into a documented bounded price formula. With current
  deterministic identification rules the range will usually collapse to one
  exact price; if identification later becomes uncertain, the same UI and
  settlement contract can show a genuine lower/upper range.
• Display scope, eligible count range, minimum/maximum price, provider identity,
  available funds, and maximum possible provider debt before confirmation.
• Re-query at confirmation. Changes to the marked object, container contents,
  eligibility, provider capability, debt, or price require a fresh quote.
• Cast through the normal outcome-bearing identification API and calculate the
  final charge from the actual number identified. Zero actual items means zero
  cash and zero debt.
• Allow explicitly confirmed partial funding through the provider-specific
  credit ledger in feat(server): persist provider-specific service debt classic#267. Existing debt to that smith must be
  repaid before another paid service; other providers are independent.

Provider metadata

Every participating smith needs a canonical authored npc_id for debt and
confirmation identity. Audit whether combat level is a legitimate
identification capability; if not, author a dedicated low-frequency custom
service-rank attribute and register only its typed content extension metadata.
Do not dispatch or persist by display name, map path, interface filename, or
runtime object count.

Acceptance criteria

• Every Smith service provider is inventoried with a unique stable npc_id
  and an explicit, reviewed capability input.
• Marked, marked-container, and normal inventory scopes exactly match
  Classic identification behavior; text does not promise recursive or
  otherwise broader identification than the native spell performs.
• The documented formula produces a bounded minimum/maximum price from the
  queried eligible-item work range, with exact rounding and caps.
• Preview and confirmation use the same formula and state evidence; drift
  requotes without casting or charging.
• The final cash plus new debt is calculated from actual items identified,
  never from attempted items or the quote maximum, and cannot exceed the
  confirmed maximum.
• Already identified, invisible, non-identifiable, over-capability, empty
  container/inventory, and missing-marked-object cases cast nothing and cost
  nothing.
• Partial and full identification, insufficient funds, partial funding,
  prior provider debt, repayment, repeat confirmation, and provider
  relocation/rename are tested.
• Existing CastIdentify() callers remain compatible; this service uses
  the work-query/outcome APIs from feat(server): make scripted spell services work-aware classic#264.
• python3 tools/validate.py, git diff --check, derived Classic server
  tests, an isolated runtime scenario, and repository-required checks pass.

Dependencies and boundaries

Blocked by atrinik/classic#264,
including work queries (#265/#266), actual identification outcomes (#248), and
provider credit (#267).

This issue owns authored Smith pricing, provider metadata, dialogue, and
integration. It does not change identification spell scope or implement the
future Go commerce services tracked by
atrinik/server#52.