### What problem does this PR solve?
As title:
implement:
```
/api/v1/messages/search GET
/api/v1/messages GET
/api/v1/messages/<memory_id>:<message_id>/content GET
/api/v1/memories/<memory_id>/config GET
/api/v1/messages/<memory_id>:<message_id> PUT
```
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
## Summary
- Implemented the Go API endpoint for Memory message forgetting:
- `DELETE /api/v1/messages/{memory_id}:{message_id}`
- Added route registration for the Memory message DELETE endpoint only.
- Added request path validation for `memory_id:message_id`.
- Added service logic to mark a message as forgotten by setting
`forget_at`.
- Preserved Python-compatible response behavior:
- Success returns `code: 0`, `message: true`, `data: null`.
- Added focused unit tests for message path parsing and invalid message
ID handling.
- Fixed Linux cgo linker config to use the installed shared PCRE2
library so Go tests/builds can run in this environment.
## Related Issue
Closes: #15240
## Change Type
- [x] Feature
- [x] Test
- [x] Build / CI compatibility
## Implemented API
- `DELETE /api/v1/messages/{memory_id}:{message_id}`
## Real Behavior Proof
Validated with targeted Go tests:
```bash
/tmp/go1.25.0/bin/go test ./internal/handler ./internal/router
```
Result:
```text
ok ragflow/internal/handler
? ragflow/internal/router [no test files]
```
Validated server entrypoint build:
```bash
/tmp/go1.25.0/bin/go build -o /tmp/ragflow-server-main ./cmd/server_main.go
```
Result:
```text
build succeeded
```
Validated patch formatting:
```bash
git diff --check
```
Result:
```text
no whitespace errors
```
## Checklist
- [x] Implemented only `DELETE
/api/v1/messages/{memory_id}:{message_id}`.
- [x] Did not implement unrelated Memory message APIs.
- [x] Added route registration.
- [x] Added handler validation.
- [x] Added service-level memory access check.
- [x] Added tests.
- [x] Ran targeted Go tests.
- [x] Ran server build validation.
- [x] Ran `git diff --check`.
### What problem does this PR solve?
```
RAGFlow(user)> ocr with 'hunyuanocr@test@gitee' file './picture.png'
+----------------------------------------------------------+
| text |
+----------------------------------------------------------+
| 生活不是等待风暴过去，而是学会在雨中翩翩起舞。
——佚名 |
+----------------------------------------------------------+
RAGFlow(user)> list 'test@gitee' tasks;
+---------+----------------------------------+
| status | task_id |
+---------+----------------------------------+
| success | C3FX4MQNKY5MGC6ZFMIXIAMJKHCEBQB5 |
+---------+----------------------------------+
RAGFlow(user)> show 'test@gitee' task 'C3FX4MQNKY5MGC6ZFMIXIAMJKHCEBQB5';
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
| content | index |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
| # PDF 1: Purpose of RAGFlow
RAGFlow is an open source Retrieval-Augmented Generation (RAG) engine designed to turn raw documents into reliable context for large language models.Its purpose is to make it practical to build an Al assistant that can ans... | 1 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
```
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
---------
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
feat: Implement file upload and folder creation features
- Add file upload route in router.go
- Add file operation methods in dao/file.go
- Add util/file.go for file type detection and filename handling
- Implement file upload and folder creation endpoints in handler/file.go
- Implement file upload and folder creation logic in service/file.go
- Modify response message format in memory.go
- Add document count method in dao/document.go
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat： Add Memory function by go
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
---------
Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>
