fix(pgwire): complete the shaper error classification and keep internal detail in the log

[EnRaiha]

Why

numeric_code_to_sqlstate answered 22 of 81 codes and fell back to XX000 for the rest, so a quota, clone, move-tenant, mirror, sync, storage/WAL, cluster, config, or encryption fault reached every routed surface as an internal fault — including the shaper's own SERIALIZATION code, the exact "payload does not fit the projection" case the class should name.

An XX000-class failure also rendered its message verbatim, so a manifest path or invariant text could travel to a client on an error frame.

Fixes #338. Bottom of a two-PR stack.

What

• Mapper completion (numeric_code_to_sqlstate, 22 → 81): the remaining 59 codes carry issue Routed response-shaper errors flatten to XX000; the numeric SQLSTATE mapper covers 20 of 81 codes #338's decided class — the constraint family mirrors the Data Plane table (236xx); clone, quota, move-tenant, mirror, sync, storage/WAL, cluster, config, and encryption follow the classes the local crate::Error table already names. INTERNAL, BRIDGE, and DISPATCH keep XX000 as explicit arms.

• Six new sqlstate.rs constants: 22000, 22P02, 25006, 2BP01, 42P07, XX001.

• Hygiene: new shaping_error_message; an XX000-class failure logs the detail with its code and sends one stable summary, every other class passes through.

• Fallback bridge: error_to_sqlstate no longer ends in a blanket INTERNAL_ERROR. A variant
  with no arm of its own borrows its class through classify() and answers from this table, so the
  65 arm-less variants (balance, period lock, legal hold, retention, transitions, type guard, type
  mismatch, mirror, session and quota rejections, ...) stop reporting XX000. The bridge exposed
  RetryableSchemaChanged classifying as a plan error; it now classifies as a write conflict
  (40001), matching the retry contract its lease callers already rely on.

Validation

Run at the head of the stack (this PR plus the surface PR above it):

• cargo check -p nodedb --all-targets — clean.
• cargo test -p nodedb --lib error_map — 35 passed (mapper table covering all 59 completion codes, the three internal arms, hygiene replace/pass-through).
• cargo test -p nodedb-types — 750 passed (sqlstate constants incl. the six new ones).
• cargo clippy -p nodedb -p nodedb-types --all-targets -- -D warnings — clean.
• cargo fmt --all -- --check — clean.

Notes

The streamed responder and the DDL dispatch render through this mapper in the PR stacked above.

Tradeoffs

Tradeoff: the bridge moves RetryableSchemaChanged from a plan error to a write conflict (40001). The class change is deliberate: the lease paths retry this variant by contract.

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[EnRaiha]

Rebased onto main @ 4664c8213 and pushed (2f8f4f17c). The single conflict was in error_map.rs, where main's new Error::Shaping arm landed: that arm is kept and the fallback bridge follows it. Local evidence: cargo test -p nodedb --lib error_map — 37 pass. The branch is linear again (3 commits over main), so the streamed/DDL surfaces work can be resubmitted against main once this lands.

[farhan-syah]

Closing. Several classes in the completed table are wrong: SERIALIZATION → 22P02 reports internal encode failures as client input errors, STORAGE/WAL → 58030 renders raw detail (paths) to the client, and CLUSTER → 08006 tells drivers the connection dropped. The branch also conflicts with main after #360. The maintainers will settle the SQLSTATE table for #338 in-tree.