revert: remove CUSTOM strategy and semanticOverride support

[aidandaly24]

Description

Reverts two features that were prematurely merged:

1. CUSTOM memory strategy (beac707 / feat(memory): add CUSTOM strategy type to agentcore-cli (#677) #694) — removes the CUSTOM strategy type from the schema, CLI wizards, templates, docs, and validation
2. Semantic override (5e0f584 / feat: add semanticOverride support for SEMANTIC memory strategies #696) — removes semanticOverride field from MemoryStrategy, including schemas, types, exports, and cross-field validation

EPISODIC strategy support is intentionally preserved throughout.

What changed

• MemoryStrategyTypeSchema enum: 5 → 4 values (removed CUSTOM)
• Removed SemanticOverrideSchema, SemanticExtractionOverrideSchema, SemanticConsolidationOverrideSchema and all exports
• Removed semanticOverride field from MemoryStrategySchema and .superRefine() cross-field validation
• Removed custom option from create/add-agent wizards and CLI flags
• Removed CUSTOM Handlebars blocks from Python session templates
• Removed mapExistingMemoriesToProviders and memory deduplication logic
• Updated docs (commands.md, configuration.md, memory.md)
• Restored EPISODIC row in configuration.md (inadvertently removed by the CUSTOM revert)

Related Issue

Reverts #694, #696

Type of Change

• Other (please describe): Revert of prematurely merged features

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[github-actions]

Package Tarball

aws-agentcore-0.3.0-preview.9.0.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-713-tarball/aws-agentcore-0.3.0-preview.9.0.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	46%	6552 / 14242
🔵	Statements	45.57%	6962 / 15276
🔵	Functions	44.71%	1176 / 2630
🔵	Branches	46.09%	4331 / 9395

Generated in workflow #1479 for commit ae62347 by the Vitest Coverage Report Action