feat(ogc): apply Level 1 title naming pass across layers

[likithabommasani21]

Why

• Several layer titles use unexplained abbreviations (TDS, BHT) or don't match USGS NWIS naming conventions, per the audit in docs/ogc_conventions.md
• Level 1 changes are cosmetic (title only, no ID change), so they're non-breaking and can ship now, ahead of any Level 2 ID renames

How

• Updated titles for lakes_ponds_reservoirs, rock_sample_locations, soil_gas_sample_locations in core/pygeoapi.py
• Updated titles for latest_tds_wells, well_water_column, geothermal_wells_bht, geothermal_wells_temperature_profile, bht_measurements in core/pygeoapi-config.yml
• Updated matching titles for latest_tds_wells, well_water_column, avg_tds_wells in core/pygeoapi-config-internal.yml so the internal mount doesn't show a different name for the same layer
• No layer IDs changed
• Updated docs/ogc_conventions.md: marked these rows as implemented, dropped the bht_measurements needs-review flag, added a changelog entry

Notes

• Verified new titles appear correctly in /ogcapi/collections and /ogcapi-internal/collections responses against the local dev server
• Full test suite passes (1033 passed, 84 skipped)
• Level 2 (ID renames) is intentionally out of scope for this PR

[github-actions]

Coverage

✅ 79.35% total — gate is 75%.

Coverage for the Python files changed in this PR

Name	Stmts	Miss	Cover	Missing
core/pygeoapi.py	160	20	88%	318, 322, 331, 336, 355, 362, 387-390, 535, 540, 628, 664, 682, 689, 691, 711, 713, 725
TOTAL	160	20	88%