Add support for indexes section in .pgschemaignore

[guillaume86]

Summary

• Adds an [indexes] section to .pgschemaignore so users can keep indexes that exist in the live database but are not declared in their schema .sql files. Without this, manually-added indexes (perf hotfixes, ad-hoc operational fixes) are flagged for drop by pgschema plan.
• IgnoreConfig.Indexes + ShouldIgnoreIndex(name) mirror the existing per-object pattern.
• Inspector.buildIndexes skips ignored index names before they enter the IR, so they don't appear in dump and don't show up as drift in plan.

Fixes #406

Test plan

• Added TestIgnoreIndexes (in cmd/ignore_integration_test.go) reproducing the exact Add support for indexes to .pgschemaignore #406 scenario: a manual_perf_idx exists on a managed table, the desired schema doesn't declare it, the ignore config lists manual_*. Asserts the dump excludes it and the plan does not reference it.
• Extended TestIgnoreConfig_AllObjectTypes and TestIgnoreConfig_NilConfig to cover indexes.
• Extended TestLoadIgnoreFileFromPath_ValidTOML to round-trip the new [indexes] section.
• Full suite green locally on PG 17 (go test ./... — ~7 min).

Run just the new test:

go test -v ./cmd -run TestIgnoreIndexes

🤖 Generated with Claude Code

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Note (2026-05-23): pgproj (a downstream DACFX-shaped fork at https://github.com/guillaume86/pgproj) has adopted a hard-fork posture and will continue independently. This contribution remains open without expectation of merge; happy to address review feedback if a maintainer engages.

[greptile-apps]

Greptile Summary

This PR adds ignore support for database indexes. The main changes are:

• Adds an [indexes] section to .pgschemaignore parsing.
• Adds IgnoreConfig.Indexes and ShouldIgnoreIndex.
• Skips ignored indexes during database inspection.
• Adds tests for loader parsing, nil handling, and dump/plan behavior.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The new index ignore path follows the existing object ignore pattern.
• Constraint-backed indexes remain handled by the existing constraint flow.

_{Reviews (1): Last reviewed commit: "Add support for indexes section in .pgsc..." | Re-trigger Greptile}