docs: add godoc comments to core APIs and improve README

[AWaterColorPen]

Description

This PR completes two Phase 1 tasks:

Task: Add godoc comments (core API)

Added package-level and type/method-level documentation to the 6 core source files:

• manager.go — package doc, Manager type, all public methods (GetClients, GetDictionary, SetLogger, RunSync, RunChan, BuildTransaction, BuildSQL, NewManager)
• client.go — ClientsOption, Clients type, all public methods (RegisterByKV, RegisterByOption, SetLogger, Get, BuildDB, BuildSQL, NewClients)
• configuration.go — Configuration struct with field-level comments
• database.go — DBOption struct with DSN format examples, NewDB, getDialect
• dictionary.go — Option, Dictionary, Translator, Translate, NewDictionary
• run.go — RunChan, RunSync, BuildResultChan, BuildResultSync

Task: Improve README (Quick Start)

• Added architecture diagram showing Query → Dictionary → Clause → SQL → Database → Result flow
• Complete runnable Quick Start example with NewManager, BuildSQL, RunSync
• Common patterns section: adding filters, streaming with RunChan, inspecting SQL without executing
• Requirements section noting Go 1.22+ minimum
• Cleaner documentation table linking to existing docs

Phase 1 Status after this PR

• Upgrade Go to 1.24
• Upgrade patch dependencies
• All tests passing
• Go syntax modernization (range over integers)
• Improve README with Quick Start
• Add godoc comments (core APIs)

Phase 1 is complete after this PR merges!

[AWaterColorPen]

AI Review — LGTM ✅

Solid documentation PR. Notes:

README improvements:

• The ASCII architecture diagram clearly explains the Query → Dictionary → Clause → SQL → Result pipeline.
• The end-to-end Quick Start example with a complete main.go, generated SQL, and expected JSON output is exactly what new users need.
• "Common Patterns" section (filters, RunChan, BuildSQL) covers the most practical use cases.
• Requirement callout (Go 1.22+) prevents silent breakage for users on older toolchains.

godoc comments:

• All public types and methods are covered across manager.go, client.go, configuration.go, database.go, dictionary.go, and run.go.
• Comments follow Go conventions: sentences start with the identifier name, each explains what the symbol does and when to use it.
• The Configuration struct comments correctly note the optional semantics of each field.
• Package-level doc in manager.go includes a minimal runnable example — good for pkg.go.dev.

No logic changes — purely additive documentation. CI passes. ✅

Ready to merge.