tools: ST4 SQL/MM example factory — WKT §5.1.67 + WKB §5.1.68 (Shelf A start)

[grootstebozewolf]

claimId: none (tools / docs).

Shelf A start of the north-star path (copied here; does not wait on #741): locked SHC bag → ISO/IEC 13249-3 WKT (§5.1.67) and WKB hex (§5.1.68 Table 15) through StringTemplate 4 .stg groups. Inverse of tools/WktIntakeWalker.

tools/WktIntakeWalker/          # ANTLR pin + visitor (exists)
tools/SqlMmExampleFactory/      # bag → WKT + WKB  (this PR)
oracle/fixtures/sqlmm/          # locked smoke rows + HOLD note

What this inhabits

• templates/SqlMmWkt.stg — POINT, LINESTRING (+ EMPTY), CIRCULARSTRING, CIRCLE, COMPOUNDCURVE of LS+CS (children keep type), CLOTHOID JTS (k0,k1,L) and ISO REFERENCELOCATION.
• templates/SqlMmWkb.stg — NDR + XDR for codes 1 / 2 / 8 / 9. CIRCLE and CLOTHOID are named HOLD (κ=none). HOLD named for 13–17 / 18–21 (not Circle-as-18, not Clothoid-as-22, not WKB 13).
• Minimal Java ST4 driver (org.antlr:ST4:4.3.4 + org.antlr:antlr-runtime:3.5.3 via local jar download, same pattern as the intake walker). No Maven reactor.
• smoke.sh: locked LINESTRING bag round-trips through the pinned grammar (μ bag equals input); WKB hex stable for Point / LineString / CircularString / CompoundCurve. Local run: sqlmm example factory smoke OK. make ci-guards OK.
• GEODESICSTRING emits as LINESTRING because τ(MkChord)=TagLineString. Honest chord bag. Not TagGeodesic / WKB 13.

Rocq emit stays QEX: ticket_sqlmm_factory_emit_qed_or_qex is not reminted. This PR inhabits tools bytes only.

Engines still test the bag. No new ADR-0006 oracle keyword.

Hard no (honoured)

• No oracle protocol change
• No silent chord densify framed as curve
• No signed I/O for 13–17 / 18–21
• No MkGeodesic / geodesic_eval / unhold ADR-0007 NURBS first-cook (claimId 0007-nurbs-first-cook) #729 / first-cook expand
• No remint of 0007-intake-geodesic / 0007-sqlmm-signed-tag

Base: origin/main f409574f2501647f3979bb9552c10bcd54f3ece1.
Tip: cc6032e9a87a4c4984f3e07a65ad277459b37311.

This PR was drafted with AI assistance. Do not merge from this courier unless a human says go.